Importance of Sleep

Stages of Sleep

Whilst we may associate it with simply being a state of unconsciousness, sleep is in fact a complicated process made up of several stages. The two general stages are REM sleep (rapid eye movement) and NREM (non-rapid eye movement) sleep. NREM sleep is thought to consist of four different stages and all these stages have a different depth of sleep. The sleep cycle consists of roughly five stages, the first four being the NREM stages and then the final stage of REM sleep occurring within 90 minutes of the individual falling asleep. The REM stage initially lasts around 10 minutes with the first cycle but increases in length with each cycle. Therefore, if you sleep for an average of 8 hours, you will complete about five of these cycles.

REM Stage of Sleep

It is during the REM stage that most individuals will remember dreams, especially if they wake up naturally during this stage. If you are woken by an alarm clock or unnaturally, the remembrance of dreams will rely upon which stage of sleep you were in. It is also during REM stages that individuals may experience a sleep start or hypnic myoclonia in which they involuntary jerk suddenly, and it is often accompanied with a feeling of falling. This is wholly normal and is thought to occur because the individual has entered into sleep through the REM stage as opposed to the NREM stage. Falling to sleep in a REM stage takes place most commonly when the individual is extremely tired and catching up on sleep. It is also common for infants to enter sleep through the REM stage.

NREM Stage of Sleep

The NREM stage is divided into four separate stages, the first two being light sleeps where the heart rate slows and the individual is easily woken. The third and forth stages are a deep sleep and it becomes increasingly difficult to wake the individual. Deep sleep is essential for us as it allows our brains to relax, our muscles to repair and our immune system to re-build. Therefore, it is vital that our bodies are allowed to enter into this deep sleep state. Lack of sleep at this stage is the most common cause of sleep deprivation and needs recovering the next time the individual sleeps. If you are a carer or new parent, it is important that you are allowed to have a large period of uninterrupted sleep so you can enter into this deep sleep stage.

Why We Need to Sleep

Removing all of the science we may find that it is not the process of sleep that is so significant, it is the bodies own rejuvenation that is crucial. Sleep allows the body to restore tissues, energy levels and recover from illnesses. Equally it allows the mind to unwind, de-stress and restore mental harmony. Thus, a lack of sleep will no doubt take its toll on the individual, both mentally and physically.